F-Stop was built around a camera mechanic rather than portals: taking a photo of an object captures it, and the resulting Polaroid-like picture can be used to place that item elsewhere to solve puzzles. The Verge notes full campaign videos run under an hour, which fits its origins as a prototype.

The game dates back to 2007, when Valve ran a three-month internal experiment after the Orange Box launch, splitting into five teams to build prototypes. F-Stop applied Team Fortress 2's cel-shaded style to a mid-century vision of Aperture Science in its prime. The prototype itself features an early version of Cave Johnson, without J.K. Simmons, and the first instance of Aperture Personality Cores as puzzle companions; separately, elements of its worldbuilding later appeared in Portal 2 and Aperture Desk Job.

Access is currently limited: the Valve Cut Content Discord has gone private amid the attention, so playing the build yourself requires an invite. There is no indication from Valve of an official release, making this compilation likely the closest F-Stop will get to one. Its central idea did reach players commercially, though, in the 2023 puzzle game Viewfinder.